The use of NB, KT or LINA in variable names is not allowed.

Also do not use the variables NN, NT, VARIANT, VARSET and VERSION as these can also cause problems.

For variable names, use the same schema cross-catalog. For example, for two products of the same kind, do NOT use once "L" for length and once "L1".

This has special relevance for the Faceted search among others, in order for the variable filter to be able to really find ALL relevant products.